1. Field of the Invention
The present invention relates to methods of entering machining information and display therefor in a numerically controlled machine tool.
2. Description of the Prior Art
In a machining center as is shown in FIGS. 1 and 2 each of tools 2 encased in a magazine 1 is conventionally set in order on a spindle 4 through a tool changer 3 and used to machine a workpiece on a X-Y table 5 in response to a control panel 6 operation and subsequent commands from a control unit 7. Preparation of machining information to be entered into a numerical control unit of the machining center 8 requires development of machining elements, on a `tool` basis as shown in FIG. 3, which are specified by machining patterns of a finish contour shown in an engineering drawing, such as machining elements of centering, drilling and chamfering as to a drill hole machining, as well as translation of selection of tools, movement of the tool and machining order corresponding to a cutting configuration and the like into a language which the numerical control unit can decode. Drawing information can be translated into the machine language only by an adequately experienced programmer having substantial technical knowledge. Furthermore, the machine language, which is little associated with the drawing information, is apt to be wrongly entered. Machining information required by the numerical control unit is so much more and more complex than the drawing information of the workpiece, that programming is a time-consuming labor. Thus, in entering machining information, programming, which requires a great deal of time for a professional programmer, must be done in advance at offline status of machine.
The prior art, in trying to overcome the disadvantages, has employed an automatic programming of the machining information by the drawing information and other complementary information, in which also a specific programming language is used. Considerable training will be required to comprehend such a language and consequently a professional programmer is required. The machining information thus prepared must be ultimately translated into a language which the numerical control unit can decode, so that such a programming is usually done at offline status of machine. Furthermore, programming for a simple machining drawing which will be simple in itself may become complex, as a certain procedure must be taken, whether the machining drawing is simple or complex. In a method for eliminating these problems, machining information may be entered directly into a computer through a console key board. In this method, however, the finish machining contour is to be sequentially developed by every machine element on the `tool` basis, and the machining information thus developed is entered in machining order, which operation is considerably complex. Furthermore, when a certain machining is repeated several times in the drawing, the machining information specified by each machining element must be entered repeatedly at the corresponding times. Thus, operation of entering the information becomes disadvantageously complex to incur the risk of wrong information input as well as to require considerable hours.
In a numerically controlled machine tool, especially in a numerically controlled machine tool into which machining information of a workpiece is entered through a control panel, a number of manual control switches are required to suit the respective information inputs, resulting in requirement of a large control panel and the possibility of wrong operation of the machine.
In order to overcome these defects, the prior art has proposed the use of a push-button control switch with switching mechanism, that is a control switch to which a plurality of functions are allotted, to reduce the number of the control switches. It is true the control panel becomes smaller, but at the same time control becomes more complicated, inducing control error, and also the control circuit is so complicated to cause wrong operation and to make circuit check as well as maintenance more difficult.
As the numerical control language for programming is only a symbol of each function, it is difficult to guess the original function or operation from it. As the program check is also performed through the above-mentioned difficult language, it required considerable hours and hard labor, and furthermore, errors, if any, will be difficult to be detected.